Genus

Species

Synonyms

Characters

Liopleurodon is a genus of carnivorous marine reptiles from Jurassic Europe. Scientists believe that two species of Liopleurodon, L. ferox and L. pachydeirus, lived during the Jurassic Period, around 160-150 million years ago. It was a strong swimmer and likely one of the greatest predators of its time. It was about 23 feet long and it weighed about 2 tons. Its skull alone was 5 feet long.

Contents

Description

Size

To estimate the maximum size of Liopleurodon has been a controversial subject. The palaeontologist L. B. Tarlo thought that the full body length of a pliosaur (including Liopleurodon) can be guessed from its skull length. Tarlo claimed that the skull of a pliosaur is typically 1/7 of the total length. The largest known skull belonging to L. ferox is 34 ft long.[1] Based on Tarlo's hypothesis, this specimen would be around 34 ft long. But, the case of Kronosaurus exposed some doubts of the accuracy of Tarlo's suggestion.[1]

New research on pliosaur anatomy has cast doubt on Tarlo's hypothesis of the size of pliosaurs and showed that pliosaur skulls were typically just 1/5 of the body length. An exceptionally well-preserved skeleton of L. ferox is in the Institut und Museum für Geologie und Paläontologie der Universität Tübingen in Germany. This specimen is around 15 ft long.[2]
Fossil remains of another specimen identified as L. ferox have been excavated from an Oxford Clay formation near Peterborough. This specimen has been estimated to be 21 ftt in length with a skull length of about 4.1 ft and is thought to be an adult.[3] An adult L. ferox would have averaged 16-23 long.[1]

Some fossils dug up from the Kimmeridge Clay formation in England show a much larger taxon, possibly up to 49 ft long, but these have not been assigned to the Liopleurodon genus.[1]

Part of a jaw bone that measures 9.43 ft is at the Oxford University Museum of Natural History: it is estimated that the total length of the jaw is more than 9.43 ft. The was first assigned to the Stretosaurus genus (as Stretosaurus macromerus),[4] but is now thought to come from the Liopleurodon genus and has been renamed L. macromerus. The genus Stretosaurus later became a junior synonym of Liopleurodon,[5] but it has been re-classified as Pliosaurus macromerus.[6]

Classification

Now, there are three recognized species within Liopleurodon. L. ferox is well known, the rarer L. pachydeirus, described by Seeley as a Pliosaurus (1869),[7]and L. rossicus, known from the early Volga Beds of Russia. This species was first described by Novozhilov (in 1948) as being from Pliosaurus, and is the type species of the genus Strongylokroptaphus.[8][9] Just L. ferox is known from more or less complete skeletons.

History

The genus name Liopleurodon was coined by Henri Émile Sauvage in 1873 based on too poor remains made up of three 70 mm teeth. One tooth, found near Boulogne-sur-Mer, France in layers, was named Liopleurodon ferox, one from Charly, France was named Liopleurodon grossouvrei, while a third found near Caen, France was first described as Poikilopleuron bucklandi and ascribed by Sauvage to the species Liopleurodon bucklandi. Sauvage did not ascribe the genus to any particular group of reptiles in his descriptions.[10]

Most Liopleurodon fossils have been found in England and France, with one younger species known from Russia. Fossil specimens of the same time are known from Germany.[11]

Paleobiology

Four strong fin-like limbs suggest that Liopleurodon was a mighty swimmer. Its four-flipper mode of propulsion is feature of all plesiosaurs. A study that used a swimming robot has shown that while this form of force is not especially efficient, it provides very good acceleration - a desirable trait in an ambush predator.[12][13] Studies of the skull have shown that it likely could scan the water with its nose to check the source of some smells.[14]

Liopleurodon in The Land Before Time

Liopleurodon has so far only appeared in The Land Before Time IX: Journey to Big Water, serving as the main antagonist of the film. They are referred to as "Sharptooth Swimmers" by the characters. It is notable for being one of the rather few Sharpteeth antagonists that have survived. It is possible it was depicted because of its appereance in the well-known BBC Documentary, Walking with Dinosaurs.

Liopleurodon in The Land Before Time, based on the one seen in the ninth film, are dull brown in color with darker oval spots along each side of their spine. Their underbelly is a lighter shade of dull brown, and the circle around their eyes are the same color as their spots. They are notable for their yellow, appearing pupiless eyes, which only rarely show a slight sliver of pupil.

↑Noè, L.F.; Smith, D.T.J.; Walton, D.I. (2004). "A new species of Kimmeridgian pliosaur (Reptilia; Sauropterygia) and its bearing on the nomenclature of Liopleurodon macromerus". Proceedings of the Geologists' Association115: 13–24.

↑Seeley, H.G. (1869). Index to the Fossil remains of Aves, Ornithosauria, and Reptilia, from the Secondary System of Strata arranged in the Woodwardian Museum of the University of Cambridge.